Thermometer.



Patented September 6, 1904.

UNITED STATES PATENT QEEICE.

lVlLLIAM F. FRUFHAUF, OF NlllV YORK, N. Y.

THERMOMETER.

SPECIFICATION forming part of Letters Patent No. 769,474, dated September 6, 1904.

Application led November 9, 1903. Serial No 180,384. (No morlubl To 11,/ Z wil/om it may concern:

Be it known that I, "ILLIAM F. FRUEHAUF, a citizen oi' the United States, residing in New York. boroug'h ot' Brooklyn` in the State ot New York, have invented certain new and useful Improvements in Thermometers, ot which the following is a specification.

This invention relates to thermometers, and more especially to clinical thermometers; and the object of the invention is to provide a quick-acting thermometer of this type.

For this purpose the invention consists of a clinical thermometer, comprising a suitable thermometer-tube and a bulb at the lower end of said tube.

In the accompanying' drawings, Figure l is an elevation of a thermometer embodyingl my invention. Fig. 2 is a vertical central section through the bulb and a portion of the tube. Fig. 3 is a horizontal section on line 3 3, Fig'. Q. Fig. 4 is an elevation ot' a moditied form of thermometer embodying my invention. Fig. .5 is a vertical central section through the bulb and a portion of the tube ot said modified form oi' thermometer. Fig. 6 is a horirontal section on line 6 6, Fig. 5, and Fig. 7 is a horizontal section on line 7 T, Fig. 1, across the thermometer-tube.

Similar letters of reference indicate corresponding parts.

Referring to the drawings, A indicates the thermometer-tube, which is of the usual or any suitable cross-section-i'or example, that indicated in Fig'. 7 At one end ot' the tube and communicating therewith is arranged the bulb B. W'ithin said bulb is located a hollow core C. The core C and walls of the bulb B are connected at the bottom. The walls oi' the bulb are extended beyond the core-walls, and rounded and closed, as shown at D, so as to close the lower end of the core. Between the core C and the exterior walls b o'tA the bulb is the mercury-chamber oi' the bulb, in which the mercury E is contained. The core C retains the mercury in the form ot' a thin layer adjacent the walls ot' the bulb. rlhe walls 7) preferably taper at their upper ends, as shown, to the bore a oi' the tube. The

core C is closed from the mercury-chamber.

VIt is preferably made conical at its upper end in conformity with the contraction of the walls and arranged in line with said bore.

lt is obvious that the invention may be embodied in other than clinical thermometers, and in clinical and other thermometers having a diil'ercnt shape ot' bulb than that shown.

ln order to increase the strength of the bulb, spirally-arranged partitions may be located between thc core C and the bulb-walls l). as indicated in Fig. These partitionwalls (l preferably extend `from the bottom of the mercury-cham ber of the bulb spirally through the same to nearly the top of said chamber, where they terminate.

A clinical thermometer, such as either of the forms shown, embodying my invention is employed by placing' the bulb of the same beneath the tongue of the patient or at any other desired point. The mercury in the bulb B rapidly expands and rises in the tube until, when it ceases to further expand, the temperature is indicated by the position of the upper end of the mercury in the bore a against the scale upon the tube. The mercury rises with much greater rapidity than in a clinical thermometer oi' the ordinary type having a bulb containing' a solid body of mercury. It is found that when approximately the proportions indicated in Fig. 2 are followed the mercury rises in about one-third the time required for a solid mercury-bulb of the correspondingsize. Owing to the more rapid action the bulb may be made larger than in a clinical thermometer of the ordinary type and more mercury employed, whereby the weightv is increased and the shaking down ot' the mercury into the bulb after operation rendered easier and more rapid. The use otl the larger quantity of mercury enables also the employment of a thermometer-tube having a larger bore, so that with the lens usually employed the reading ot' the thermometer is rendered easy. It is possible thus to use a tube of the size heretofore commonly used for a three-minute7 thermometer in a thermometer made according to my invention, which will operate in one minute, so that the ease of reading of a threeminute thermometer is obtained in a therthe lower end wall of the bulb, substantially as set forth. l

2. A clinical thermometer, consisting of a tube, a bulb, and avhollow Closed core within saidY bulb, substantially as set forth.

In testimony that I claim the foregoing as my invention I have signed my name in presence of two subscribing witnesses.

WILLIAM F. FRUEHAUF.

Ifitnesses:

HENRY J. SUHRBIER, FRANK E. BoYoE. 

